Tube-mill



H. W. HARDINGE.

TUBE MILL. APPLICATION HLED SEPT. l2, 1915: 1,348,642. Patented Aug. 3, 1920.

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gvwemroz `drical portion and the pieces HARRY W. HARDINGE, 0F NEW YORK, Y.

TUBE-MILL.

To all whom. it may concer/n:

Be it known that I, HARRY W. HARDINGE, a citizen of the United States, residing at New York, county and State of New York, have invented certain new and useful Improvements in Tube-Mills, of which the fol-V lowing is a full, clear, and exact description.

Iii disintegrating ores for concentration or like purposes the particles must, as is well known, be reduced to a. certain degreen of fineness. These particles are called fnesf and coarser particles that pass out with the fines must be re-ground. My present invention relates to this rcgrinding, and its object is to provide simple and effective means forl use with tubemills and the like by which coarse particles which would otherwise escape may be trapped at the outlet and be carried back to the inlet of' the mill and discharged into the same. To this and other ends the invention consists in the novel features and combinations hereinafter described.

One form ol the invention is illustrated in the accompanying drawing, in which- Figure 1 a side view, partly in section, of a conical mill equipped with my invention.

Fig. 2 is a section on line 2 2, looking in the direction of the arrows.

The mill shown is the well known cal mill, comprising a tapered barrel or drum 1() with inlet and outlet trunnions 11 and 12, respectively, mounted in suitable bearings 13, 14. The drum is rotated about its longitudinal axis by means of a large gear 15.

In a. conical mill the material undergoing disintegration assorts itself according to size, the larger pieces occupying the cylingrowing smaller and smaller toward the outlet trunnion. A stream of water is kept flowing through the barrel, and as it'issues from t'he outlet trunnion it carries the fines with it. At the same time more or less material may also escape into the trunnion and be washed out with the fines.

I accordingly provide a trap at the.inner end of the outlet trunnion, in which coarse particles may sink. This trap may be formed of a channel iron bent to circular shape with the flanges extending inwardly, and placed inside the trunnion casting, as

Specification of Letters Patent.

coni- Patented Ang. 3, 1920.

Application filed September ,12, 1916. Serial No. 119,612.

' shown at 1G, Fig. 1. Then if any coarse particles find their way over the innermost flange they wlll sink while the particles line enough to float pass on, the outermost flange .of the channel iron serving as a dam or baliie to prevent outflow of such coarse particles as might by their momentum be earried on vinto the trunnion.

For the purpose of' taking the collected coarse particles from the trap and returning them t0 the mill at the inlet end for regrinding, I provide one or more helical conveyer pipes 17. Each pipe has one'end opening into the trap, (if more than one pipe are used they are connected to trap equidistantly around the same), and the pipes are bent in helical fashion half-wayaround the mill and have their other ends inserted into the inlet trunnion l1.

Now as the mill revolves the inlet ends of the conveyer will come successively under the coarse material in the circular trap. Such material falls into the open end of the pipe, and as the mill revolves (in the direction of the arrows) thematerial is carried alongthe helical pipe on the principle of the Archimedes screw until it reaches the outlet end of the pipe, and fallsqnto the inlet trunnion. In this way the coarse particles intercepted by the trap or dam are reintroduced into the mill immediately.

The Llischarge ends of the conveyers are extended into theinlet trunnion so that material passing into the mill will not fall into the conveyers when the open ends thereof are in lower position (as shown in Fig. 1) and to prevent material discharged by one conveyer at the top of the trunnion from falling into the open end of a conveyer below, the discharge ends of the conveyers may be staggered axially as in Fig. 1. To prevent any material fed into the inlet end of the trunnion from finding its way into the discharge orifices of the conveyer tubes the latter are extended into the trunnion, as shown.

It is to be understood that the invention is not limited tothe construction herein specifically illustrated but can be embodied in other forms without departure from its spirit.

I claim:

Y 1, A grinding'mill comprising in combination a rotatable drum having an inlet and a conical outlet portion, a substantiallx etn annular inwardly-extending bale within said drum adjacent the exit thereof, and a pitched conduit rotatable with vseid drum and communicating at one end with the interior of said drum adjacent to said 'baflie on the side toward the exit and connected at its other end to emptyinto said drum on the other side of said baffle.

2. In a tubemill, in combination, a rotatable drum having an inlet and a conical outlet portion, means comprising a conduit rotatable with said drum for conveying material from the outlet of said drum to the inlet thereof, Said conduit being in the form of a spiral of increasing then diminishing radius, and means at. the delivery end of the outlet for causing only the coarser particles to enter said conduit.

3. A grinding mill comprising in combination, 'a rotatable drum having an inlet and a conical outlet portion, a substantially annular inwardly extending bafie secured within. said drum in the pathof the matcrial being ground, and means for automatically returning coarse material to said drum for regrindin saidrmeans compris ing a conveying con uit rotatable with said drum and connected at its opposite ends to said drum on opposite sides of said baffle.

Ln testimony whereof I hereunto ailix my signature.

HARRY W. HARDINGE. 

